Another Isekai manga that I read recently that was written by Redo of Healer author and this one is slightly on the upper curve for Isekai series if slightly generic at the moment. The World's finest assassin or Ansatsu Kizoku is an Isekai series which had a Professional Assassin reincarnated as the main character. Betrayed by the organization whom he served a lifetime as the finest Assassin, the main protagonist is given a second chance by a Goddess to retain the life experience from his former life along with some powerups in exchange of assassinating a Hero once the Demon Lord is slain in order to prevent the world's end. Thus the main protagonist is reborn in aristocrat family as a typical Isekai mary-sue only to face even more overpowered adversary taking the Hero's mantle.
On Surface level, Ansatsu Kizoku is another Isekai series that tried to mimic the same success of Eminence in Shadow which turns out quite well with steady support for anime adaptation. Some difference is that the Harem size of the protagonist in Eminence in Shadow is smaller and the main protagonist is being less Chuuni. The author of Ansatsu Kizoku actually also happens to be Rance Series fans and just like Kaifuku Jutsushi, this series also had plenty of the worldbuilding aspects based on Rance series with a slight dash of Tears to Tiara. Considering the Demons that serve main adversary in the setting are based on Rance Mazokus which are near immortal being that can only be slain by Hero's special power. The Hero in Ansatsu Kizoku itself, is pretty much combination of Charlotte Dunois and Arios Theoman whose bond with the main protagonist will determine the ending of this series. As of now Ansatsu Kizoku works just fine as an Isekai series but time will tell if it will have enduring popularity that most Isekais unable to attain.